Multi-wide keytops are utilized in computer keyboards for a number of commonly used function keys, such as the spacebar, the shift keys, and the entry key. In most multi-wide keytop applications, the extra width of the keytop extends parallel to the width of the keyboard. However, in keys such as the entry key, the extra width of the keytop extends from front to back, and sometimes extends transverse to the keyboard as well.
Keytops spanning the width (or height) of at least two normal key spaces (about 1.5 inches in length) and larger are typically designed to accept a crank or "leveling bar" that converts a pushing motion at one end of the keytop into a pulling motion at its opposite end. This mechanism allows a large key to be guided in the same manner as a normal keytop. The operative plunger supporting the keytop can be positioned either at its center or off-center. The leveling bar assures that a large keytop can be manually operated by the user at an off-center location about its top area without binding of the keytop supports. Leveling bars are typically steel wire forms that move within their mating plastic parts with substantial clearance to accommodate the necessary tolerances permitted in keyboard assembly to accommodate differing materials, molding procedures and fabricating techniques. The required clearances between the leveling bars and mating plastic parts result in objectionable noise or rattle when the keytop is depressed or operated.
The present invention was designed to eliminate the loose connection between a leveling bar and its mating keyboard parts without modifying their structure or interfering with their intended purposes. It can be readily provided in a keytop assembly without substantial additional parts, expense or fabrication steps.